Control device and control method for continuously variable transmission

ABSTRACT

A control device for a continuously variable transmission performs feedback control so that an actual transmission control value becomes a target transmission control value. The control device includes a phase lead compensation unit configured to perform phase lead compensation of the feedback control, a phase delay compensation unit configured to perform phase delay compensation of the feedback control, a first peak value frequency determination unit configured to change a peak value frequency of the phase lead compensation according to a transmission ratio of the continuously variable transmission, and a second peak value frequency determination unit configured to change a peak value frequency of the phase delay compensation based on the peak value frequency of the lead compensation.

This is a U.S. national phase application of PCT/JP2018/032694, filed onSep. 4, 2018, which claims priority to Japanese Patent Application No.2017-178287, filed on Sep. 15, 2017. The entire disclosure of JapanesePatent Application No. 2017-178287 is hereby incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a control device and a control methodfor a continuously variable transmission mounted in a vehicle.

BACKGROUND ART

In Japanese Unexamined Patent Publication No. 2002-106700, disclosed isa technique relating to transmission control of a continuously variabletransmission, that does lead compensation of a target transmission ratioby the amount of response delay of the actual transmission ratio withrespect to the target transmission ratio.

With the continuously variable transmission, there are cases whenvibration is caused in the longitudinal direction by the resonancefrequency of the powertrain. When there is insufficient stability of thetransmission ratio of the continuously variable transmission withrespect to torque fluctuation of the powertrain, longitudinal vibrationconceivably occurs linked with the torque fluctuation and gear shiftingof the continuously variable transmission. For this reason, leadcompensation is performed, and it is conceivable that by increasing thestability of the transmission ratio of the continuously variabletransmission, in other words, damping, it is possible to suppresslongitudinal vibration. As lead compensation, it is conceivable to fixthe lead amount for the peak value frequency and perform leadcompensation. The peak value frequency is the frequency at which thelead amount according to frequency shows a peak. However, depending onthe operating state of the vehicle, there is the risk that the leadamount may be insufficient, and that sufficient damping performancecannot be obtained. On the other hand, with lead compensation, when thelead amount is made larger, high frequency gain becomes larger, so ifthe lead amount is too large, there was the problem that thetransmission ratio control system becomes unstable.

The purpose of the present invention is to provide a control device of acontinuously variable transmission for which it is possible to obtain adamping effect while ensuring stability of the transmission ratio of thecontinuously variable transmission that performs lead compensation.

SUMMARY

The present invention is a control device for a continuously variabletransmission that performs feedback control so that an actualtransmission control value becomes a target transmission control value,comprising a phase lead compensation unit that performs phase leadcompensation of the feedback control, a phase delay compensation unitthat performs phase delay compensation of the feedback control, a firstpeak value frequency determination unit that changes the peak valuefrequency of the phase lead compensation according to the transmissionratio of the continuously variable transmission, and a second peak valuefrequency determination unit that changes the peak value frequency ofthe phase delay compensation based on the peak value frequency of thelead compensation.

Thus, even if the transmission ratio changes, and the resonancefrequency of the powertrain changes, by changing the peak valuefrequency of the phase lead compensation according to the transmissionratio, it is possible to suppress frequency deviation between theresonance frequency and the peak value frequency of the phase leadcompensation. For this reason, it is possible to avoid a reduction inthe suppression effect by phase lead compensation according to changesin the resonance frequency. Also, by setting the delay amount, it ispossible to ensure the stability of the transmission control system in acase when the lead amount is made larger. Also, by changing the peakvalue frequency of the phase delay compensation based on the peak valuefrequency of the phase lead compensation, it is possible to avoid lowfrequency control excitation while avoiding vehicle vibration caused bypowertrain resonance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a vehicle including atransmission controller of an embodiment.

FIG. 2 is a schematic block diagram of the transmission controller ofthe embodiment.

FIG. 3 is a drawing showing an example of a Bode diagram of a phase leadcompensator.

FIG. 4 is a drawing showing an example of a block diagram showing themain parts of a transmission ratio control system.

FIG. 5 is a flow chart showing an example of control performed by thetransmission controller.

FIG. 6 is a drawing representing phase delay frequency characteristics.

FIG. 7 is a drawing representing the relationship between the peak valuefrequency of the lead compensation and the peak value frequency of thedelay compensation.

FIG. 8 is a drawing showing the change in PT resonance frequency Fptaccording to the transmission ratio Ratio.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic block diagram of a vehicle including atransmission controller of an embodiment. The vehicle comprises anengine 1 as a power source. The power of the engine 1 is transmitted toa drive wheel 7 via a torque converter 2, a first gear train 3, atransmission 4, a second gear train (final gear) 5, and a differentialdevice 6 configuring a powertrain PT. A parking mechanism 8 thatmechanically locks the output shaft of the transmission 4 to benon-rotatable when parking is provided on the second gear train 5.

The torque converter 2 has a lock-up clutch 2 a. When the lock-up clutch2 a is engaged, there is no slipping of the torque converter 2, and thetransmission efficiency of the torque converter 2 improves. Hereafter,the lock-up clutch 2 a is noted as LU clutch 2 a.

The transmission 4 is a continuously variable transmission having avariator 20. The variator 20 has a pulley 21 that is the primary pulley,a pulley 22 that is the secondary pulley, and a belt 23 that isstretched around between the pulleys 21, 22. The pulley 21 configures adriving side rotation element, and the pulley 22 configures a drivenside rotation element.

The pulleys 21, 22 respectively have: a fixed conical plate, a movableconical plate that is placed opposing a sheave surface with respect tothe fixed conical plate and that forms a V-groove with the fixed conicalplate, and a hydraulic cylinder that is provided on the back surface ofthe movable conical plate and that displaces the movable conical platein the axial direction. The pulley 21 has a hydraulic cylinder 23 a, andthe pulley 22 has a hydraulic cylinder 23 b.

When the hydraulic pressure supplied to the hydraulic cylinders 23 a, 23b is adjusted, the V-groove width changes, the contact radius betweenthe belt 23 and each pulley 21, 22 changes, and the transmission ratioof the variator 20 changes continuously. The variator 20 may also be atoroidal type continuously variable transmission.

The transmission 4 further comprises a sub transmission mechanism 30.The sub transmission mechanism 30 is a transmission mechanism of twoforward gears and one reverse gear, and as the forward transmissiongears, there is 1^(st) gear, and 2^(nd) gear that has a smallertransmission ratio than 1^(st) gear. The sub transmission mechanism 30has the variator 20 provided in series in the power transmission pathfrom the engine 1 to the drive wheel 7. The sub transmission mechanism30 may be directly connected to the output shaft of the variator 20 asshown in this example, and may also be connected via a powertransmission mechanism such another gear shift or a gear train, etc.Alternatively, the sub transmission mechanism 30 may also be connectedto the input shaft side of the variator 20.

The vehicle has: an oil pump 10 that is driven using a portion of thepower of the engine 1, a hydraulic control circuit 11 that adjusts thehydraulic pressure generated by the oil pump 10 and supplies that toeach part of the transmission 4, and a transmission controller 12 thatcontrols the hydraulic control circuit 11. The hydraulic control circuit11 is configured from a plurality of flow paths and a plurality ofhydraulic control valves. The hydraulic control circuit 11 controls theplurality of hydraulic control valves to switch the hydraulic supplypath based on transmission control signals from the transmissioncontroller 12. Also, the hydraulic control circuit 11 adjusts thenecessary hydraulic pressure from the hydraulic pressure generated bythe oil pump 10, and supplies the adjusted hydraulic pressure to eachpart of the transmission 4. By doing this, shifting of the variator 20,changing of the gears of the sub transmission mechanism 30, andengagement and release of the LU clutch 2 a are performed.

FIG. 2 is a schematic block diagram of the transmission controller 12 ofthe embodiment. The transmission controller 12 has: a CPU 121, a storagedevice 122 comprising RAM⋅ROM, an input interface 123, an outputinterface 124, and a bus 125 that connects these to each other.

The input interface 123 has input, for example, the output signal of anaccelerator opening sensor 41 that detects an accelerator opening APOexpressing the operating amount of an accelerator pedal, an outputsignal of a rotation speed sensor 42 that detects the input siderotation speed of the transmission 4, an output signal of a rotationspeed sensor 43 that detects a rotation speed Nsec of the pulley 22, andan output signal of a rotation speed sensor 44 that detects the outputside rotation speed of the transmission 4.

The input side rotation speed of the transmission 4, in specific terms,is the rotation speed of the input shaft of the transmission 4, in otherwords, rotation speed Npri of the pulley 21. The output side rotationspeed of the transmission 4, in specific terms, is the rotation speed ofthe output shaft of the transmission 4, in other words, the rotationspeed of the output shaft of the sub transmission mechanism 30. Theinput side rotation speed of the transmission 4, for example, may alsobe the rotation speed of a position sandwiching the gear train, etc.with the transmission 4, such as the turbine rotation speed of thetorque converter 2, etc. The same is also true for the output siderotation speed of the transmission 4.

The input interface 123 has input, for example, an output signal of avehicle speed sensor 45 that detects a vehicle speed VSP, an outputsignal of an oil temperature sensor 46 that detects an oil temperatureTMP of the transmission 4, an output signal of an inhibitor switch 47that detects the position of a select lever, an output signal of arotation speed sensor 48 that detects a rotation speed Ne of the engine1, an output signal of an OD switch 49 for expanding the transmissionrange of the transmission 4 to a transmission ratio smaller than 1, anoutput signal of a hydraulic sensor 50 that detects the hydraulicpressure supplied to the LU clutch 2 a, an output signal of a hydraulicsensor 52 that detects a secondary pressure Psec that is the hydraulicpressure supplied to the pulley 22, an output signal of a G sensor 53that detects the longitudinal acceleration of the vehicle, etc. Alsoinput to the input interface 123 are torque signals of engine torque Tefrom an engine controller 51 that controls the engine 1.

Stored in the storage device 122 are a transmission control program ofthe transmission 4, and various types of maps, etc. used for thetransmission control program. The CPU 121 reads and executes thetransmission control program stored in the storage device 122, andgenerates transmission control signals based on various types of signalsinput via the input interface 123. Also, the CPU 121 outputs thegenerated transmission control signals to the hydraulic control circuit11 via the output interface 124. Various types of values used with thecalculation processing by the CPU 121 and the calculation results of theCPU 121 are stored as appropriate in the storage device 122.

The transmission 4 may generate longitudinal vibration at a PT resonancefrequency Fpt that is the resonance frequency of the powertrain PT. Thelongitudinal vibration is thought to occur with coupling of torquefluctuation and shifting of the transmission 4 when there isinsufficient stability of the transmission ratio of the transmission 4with respect to torque fluctuation of the powertrain PT. For thisreason, lead compensation is performed, stability of the transmissionratio of the transmission 4 is ensured, and by increasing damping, thelongitudinal vibration is suppressed.

However, depending on the traveling state of the vehicle, as isexplained next, there are cases when a sufficient damping effect usinglead compensation cannot be obtained. FIG. 3 is a drawing showing anexample of a Bode diagram of a phase lead compensator. The horizontalaxis of the Bode diagram shows a logarithmic display of frequency. FIG.3 shows a case of performing secondary phase lead compensation. Peakvalue frequency Fpk is the frequency at which a lead amount A accordingto frequency shows a peak, and is set according to the targetedfrequency by phase lead compensation. The targeted frequency, inspecific terms, is the PT resonance frequency Fpt. For this reason, thepeak value frequency Fpk is set to the PT resonance frequency Fpt, forexample. Lead amount Apk shows the lead amount A according to the peakvalue frequency Fpk.

A curve C shows an example of the lead amount A according to frequency.The lead amount A according to frequency is the lead amount A of thephase lead compensation, and is the lead amount A according to thevibration frequency of torsional vibration of the input shaft of thetransmission 4. The lead amount A according to frequency may beunderstood to be the lead amount A corresponding to a certain frequencysuch as the PT resonance frequency Fpt, for example, of the curve C.With FIG. 3, as the gain G, the gain corresponding to the curve C isshown.

Here, for suppression of longitudinal vibration, as phase leadcompensation, it is conceivable to fix the lead amount Apk in the peakvalue frequency Fpk and perform phase lead compensation. Said anotherway, it is conceivable to fix the lead amount A according to frequencyto the curve C, for example, and perform phase lead compensation.However, depending on the operating state of the vehicle, there weretimes when the lead amount A was insufficient, and a sufficient dampingeffect could not be obtained. On the other hand, the damping effecttends to become greater the more the lead amount Apk of the peak valuefrequency Fpk increases. For this reason, it is conceivable to make thelead amount Apk according to frequency be variable according to theoperating state of the vehicle. However, when the lead amount Apk isincreased, the gain G also increases, so if the lead amount Apk is madetoo large, there is concern that a transmission ratio control system 100described later will be come unstable. Also, the stability of thetransmission ratio control system 100 differs according to the operatingstate of the vehicle.

On the other hand, when the lead amount Apk is made larger, when thestate of the transmission controller 12 changes, there are cases whenthe lead amount Apk becomes unsuitable. In light of that, in addition tophase lead compensation, it is desirable to perform phase delaycompensation. However, depending on the operating state of the vehicle,there is concern that there will be an insufficient delay amount B, andthat vehicle vibration will occur due to PT resonance. Also, when thereis too much delay amount B, there is the risk that the control systemwill become unstable, and low frequency control excitation will occur.

In light of that, the transmission controller 12 (hereafter also notedas controller 12) performs the transmission control explained hereafter.Hereafter, use of a transmission ratio Ratio of the variator 20 as thetransmission ratio of the transmission 4 is explained. The transmissionratio Ratio is a collective name for the transmission ratios of thevariator 20 including actual transmission ratio Ratio_A, targettransmission ratio Ratio_D, and reached transmission ratio Ratio_Tdescribed hereafter.

FIG. 4 is a control block diagram showing the main parts of thetransmission ratio control system of the embodiment. The transmissionratio control system 100 performs feedback transmission control of thetransmission 4 by performing transmission ratio control of thetransmission 4 so that the actual transmission control value becomes thetarget transmission control value. The transmission ratio control system100 is configured from the controller 12, an actuator 111, and thevariator 20.

The controller 12 has: a target value generating unit 131; an FBcompensator 132; a phase compensation on/off determination unit 133; alead amount determining unit 134; a lead amount filter unit 135; a firstphase lead compensator 136; a second phase lead compensator 137; a firstswitching unit 138; an on/off command filter unit 139; a sensor valuefilter unit 140; a first peak value frequency determination unit 141; adelay amount determination unit 142; a delay amount filter unit 143; asecond peak value frequency determination unit 144; a first phase delaycompensator 145; a second phase delay compensator 146; a secondswitching unit 147; a PT resonance detection unit 150; an oil vibrationdetection unit 151; and a divergence detection unit 152. FB is anabbreviation for feedback.

The target value generating unit 131 generates a target value for thetransmission control. In specific terms, the target value is the targettransmission ratio Ratio_D based on the reached transmission ratioRatio_T which is the final target transmission control value with thetransmission ratio Ratio as the transmission control value. Thetransmission control value may also be a primary pressure Ppri as acontrol parameter, for example. The reached transmission Ratio_T ispreset according to the operating state of the vehicle with a shift map.For this reason, the target value generating unit 131 reads thecorresponding reached transmission ratio Ratio_T from the shift mapbased on the detected operating state. In specific terms, the operatingstate of the vehicle uses vehicle speed VSP and accelerator opening APO.

The target value generating unit 131 calculates the target transmissionratio Ratio_D based on the reached transmission ratio Ratio_T. Thetarget transmission ratio Ratio_D is a transient target transmissionratio in the time until becoming the reached transmission ratio Ratio_T,and configures the target transmission control value. The calculatedtarget transmission ratio Ratio_D is input to the FB compensator 132.

The FB compensator 132 calculates the feedback command value based onthe actual transmission ratio Ratio_A which is the actual value of thetransmission ratio Ratio, and the target transmission ratio Ratio_D. Thefeedback command value is, for example, a feedback primary indicatedpressure Ppri_FB for eliminating an error of the actual transmissionratio Ratio_A and the target transmission Ratio_D. With the FBcompensator 132, FB gain G_FB is variable. The FB gain G_FB is the FBgain of the transmission ratio control of the transmission 4 performedby the transmission ratio control system 100, and is variable accordingto the operating state of the vehicle. The operating state of thevehicle is the transmission ratio Ratio, a rate of change α of thetransmission ratio Ratio, an input torque Tpri, etc., for example. Therate of change α of the transmission ratio Ratio, said another way, isthe gear shifting speed. The feedback command value calculated by the FBcompensator 132 (feedback primary indicated pressure Ppri_FB) is inputto the lead amount determining unit 134, and the first phase leadcompensator 136.

The phase compensation on/off determination unit 133 determines on/offof the phase lead compensation and the phase delay compensation of thefeedback primary indicated pressure Ppri_FB. The phase compensationon/off determination unit 133 determines on/off of the phasecompensation according to a pulley state value M, the indicated valuedivergence information of a divergence detection unit 152 describedlater, the FB gain G_FB, the oil vibration detection information of theoil vibration detection unit 151 described later, the PT resonanceinformation of the PT resonance detection unit 150 described later, andthe target transmission ratio Ratio_D. The pulley state value M is avalue for determining whether pulleys 21, 22 are in a state for whichlongitudinal vibration occurs, and includes rotation speed Npri, inputtorque Tsec to the pulley 22, transmission ratio Ratio, and rate ofchange α of the transmission ratio Ratio. The input torque Tsec can becalculated as a value for which the transmission ratio (gear ratio ofthe first gear train 3 and transmission ratio of the variator 20) setbetween the engine 1 and the pulley 22, for example, is multiplied bythe engine torque Te. For the transmission ratio Ratio, it is possibleto apply the actual transmission ratio Ratio_A and the targettransmission ratio Ratio_D. The transmission ratio Ratio may also be theactual transmission ratio Ratio_A or the target transmission ratioRatio_D.

In specific terms, the phase compensation on/off determination unit 133determines on/off of the phase lead compensation and phase delaycompensation of the feedback primary indicated pressure Ppri_FBaccording to all four parameters of the rotation speed Npri, the inputtorque Tsec, the transmission ratio Ratio, and the rate of change α. Thephase compensation on/off determination unit 133 may also be configuredto determine on/off of the phase lead compensation and phase delaycompensation according to any one of the parameters of the input torqueTsec, the transmission ratio Ratio, and the rate of change α. The phasecompensation on/off determination unit 133, in addition to the pulleystate value M, determines on/off of the phase compensation of thefeedback primary indicated pressure Ppri_FB also according to theengagement state of the LU clutch 2 a, the state of driver operationwith respect to the transmission ratio 4, and the presence or absence offailure.

At step S1 of the flow chart of FIG. 5 correlating to the phasecompensation on/off determination unit 133, when it is judged that allof these pulley state values M are longitudinal vibration generatingvalues, the process advances to step S2. On the other hand, when any ofthese pulley state values M is judged to be not a longitudinal vibrationgenerating value, the process advances to step S5, and it is judged tonot be PT resonance. Therefore, when judged to not generate longitudinalvibration, the process advances to step S10, and the phase compensationis turned off.

At step S2, a judgment is made of whether the LU clutch 2 a is engaged.By doing this, on/off of the phase compensation is determined accordingto the engagement state of the LU clutch 2 a. When the LU clutch 2 a isreleased, when it is judged that longitudinal vibration is notgenerated, and the process advances to step S5, and when the LU clutch 2a is engaged, it is judged that there is a state with longitudinalvibration being generated, and the process advances to step S3.

At step S3, a judgment is made of whether the state of the driveroperation on the transmission 4 is a prescribed state, and a judgment ismade of whether it is a first operating state in which the transmissionratio Ratio is greater than the prescribed transmission ratio Ratio1, ora second operating state in which the transmission ratio Ratio is in asteady state.

The first operating state is a state with the OD switch 49 OFF. Thesecond operating state is a state for which the transmission ratio Ratiois fixed by a driver operation, such as a state for which the manualrange is selected using the select lever, or a state when a manual modesuch as sports mode, etc., is selected. By judging whether the state ofthe driver operation is a prescribed state, it is possible to judge thatthe transmission ratio Ratio is continuously larger than the prescribedtransmission ratio Ratio1, or that the transmission ratio Ratio1 iscontinuously in a steady state. Thus, it is reliably judged that thetransmission ratio Ratio is in a state for which longitudinal vibrationis generated. At step S3, when judged to not be the prescribed state,the process advances to step S5, and when judged to be in the prescribedstate, the process advances to step S4.

At step S4, when judged that PT resonance occurs, the process advancesto step S6. At from step S6 to step S8, a judgment is performed ofwhether in a state for which it is possible to turn the phasecompensation on. Said another way, a judgment is made of whether phasecompensation can be executed.

At step S6, a judgment is made of whether there is a failure. Failure isa failure relating to the transmission 4 including failure of thehydraulic control circuit 11 or sensors or switches used fortransmission control of the transmission 4, for example. This can alsobe another vehicle failure related to the transmission 4.

At step S6, when judged that there is a failure, the process advances tostep S8, and execution of phase compensation is prohibited, the processadvances to step S10 and phase compensation is turned off. On the otherhand, when judged that there is no failure, the process advances to stepS7, execution of phase compensation is enabled, and the process advancesto step S9 and the phase compensation is turned on.

Returning to FIG. 4, the phase compensation on/off determination unit133 outputs an on command when phase compensation on is determined, andoutputs an off command when phase compensation off is determined. Theon/off command is input from the phase compensation on/off determinationunit 133 to the lead amount determining unit 134 and the on/off commandfilter unit 139.

The lead amount determining unit 134 determines the lead amount Apk. Thelead amount determining unit 134 is provided in the wake of the phasecompensation on/off determination unit 133. The lead amount determiningunit 134 is provided in this way in light of placement in the signalpath. The lead amount determining unit 134 determines the lead amountApk according to the on/off command, said another way, according to theon/off determination of the phase compensation. The lead amountdetermining unit 134 determines the lead amount Apk to be zero when theoff command is input. The lead amount determining unit 134 determinesthe lead amount Apk according to the operating state of the vehicle whenthe on command is input. As parameters indicating the operating state ofthe vehicle, input to the lead amount determining unit 134 are the FBgain G_FB, the rotation speed Npri, the input torque Tsec, thetransmission ratio Ratio, the secondary pressure Psec, and the oiltemperature TMP. The lead amount determining unit 134 determines thelead amount Apk according to this plurality of parameters. Said anotherway, the lead amount Apk is made to be variable according to theoperating state of the vehicle. The lead amount determining unit 134 mayalso have the lead amount Apk be variable according to at least one ofthis plurality of parameters.

By determining the lead amount Apk according to each parameter, the leadamount determining unit 134 can be made to be variable according to theoperating state, and it is possible to set the lead amount A at atargeted frequency. When increasing the lead amount A, the range atwhich stable operation is possible is limited considering therelationship with specific specifications of the transmission ratiocontrol system 100 such as the variator 20. This limit can be found inadvance by calculation or experimentation as a limit amount according toeach parameter. The lead amount Apk can be determined by furtherreducing the lead amount Apk actually determined according to eachparameter by the amount of the limit amount set according to eachparameter.

The lead amount determining unit 134 determines a first lead amount Apk1and a second lead amount Apk2 based on the determined lead amount Apk.The first lead amount Apk1 is set corresponding to when performing theprimary phase lead compensation described later, and the second leadamount Apk2 is set corresponding to when performing the secondary phaselead compensation described later. The second lead amount Apk2 is ½ ofthe first lead amount Apk1. The lead amount Apk determined according toeach parameter is set so as to correspond to the second lead amountApk2. The lead amount Apk determined according to each parameter mayalso be set so as to correspond to the first lead amount Apk1. The leadamount Apk is input from the lead amount determining unit 134 to thelead amount filter unit 135.

The lead amount filter unit 135 is provided in the wake of the leadamount determining unit 134, and performs filter processing of the leadamount Apk. The lead amount filter unit 135 is provided in this way inlight of placement in the signal path. The lead amount filter unit 135is specifically a low pass filter unit, and is configured as a firstorder low pass filter, for example. The lead amount filter unit 135configures a gain averaging unit that performs averaging of changes ofthe gain G of the phase compensation according to determination ofon/off of the phase compensation by performing filter processing of thelead amount Apk when on/off of the lead compensation is switched. Byperforming averaging of changes in the gain G, the change amount of thegain G accompanying on/off switching of the phase compensation issuppressed.

The lead amount Apk is input from the lead amount filter unit 135 to thefirst phase lead compensator 136, the second phase lead compensator 137,and the first switching unit 138. The peak value frequency Fpk from thefirst peak value frequency determination unit 141 is also input to thefirst phase lead compensator 136 and the second phase lead compensator137. Based on the lead amount Apk input to both the first phase leadcompensator 136 and the second phase lead compensator 137, and also thepeak value frequency Fpk, primary phase lead compensation of thefeedback primary indicated pressure Ppri_FB is performed. By performingphase lead compensation of the feedback primary indicated pressurePpri_FB, phase lead compensation of the feedback transmission control ofthe transmission 4 is performed. The first phase lead compensator 136and the second phase lead compensator 137 are specifically configured bya primary filter, and by performing filter processing according to theinputted lead amount Apk and the further inputted peak value frequencyFpk, the primary phase lead compensation of the feedback primaryindicated pressure Ppri_FB is performed.

The second phase lead compensator 137 is provided in series with thefirst phase lead compensator 136. The second phase lead compensator 137is provided in this way in light of placement in the signal path. Thesecond phase lead compensator 137 has the feedback primary indicatedpressure Ppri_FB for which primary phase lead compensation was performedby the first phase lead compensator 136 input. Therefore, the secondphase lead compensator 137 further performs again the primary phase leadcompensation when performing the primary phase lead compensation of thefeedback primary indicated pressure Ppri_FB. By doing this, thesecondary phase lead compensation of the feedback primary indicatedpressure Ppri_FB is performed. The second phase lead compensator 137configures the lead compensation unit together with the first phase leadcompensator 136.

The first switching unit 138 switches between when performing phase leadcompensation with the first phase lead compensator 136 and the secondphase lead compensator 137 according to the input lead amount Apk, inother words, when performing secondary phase lead compensation, and whenperforming phase lead compensation only with the first phase leadcompensator 136, in other words, when performing primary phase leadcompensation. By performing secondary phase lead compensation, anincrease in gain G is suppressed compared to when performing primaryphase lead compensation, making it possible to suppress destabilizationof the transmission control. Also, when the lead amount A of the primaryphase lead compensation according to the feedback primary indicatedpressure Ppri_FB is smaller than the prescribed value A1, while the gainsuppression effect cannot be expected, by performing the primary phaselead compensation, the gain G is decreased by frequency deviation, andit is possible to avoid the circumstance of the damping effect beingmore easily reduced. The prescribed value A1 can be set preferably to aminimum value within the range for which the gain suppression effect canbe obtained by having the phase lead compensation in secondary mode.

In this way, for performing phase lead compensation, the lead amountdetermining unit 134 and the first switching unit 138 are configuredspecifically in the following manner. Specifically, the lead amountdetermining unit 134 makes a judgment to perform primary phase leadcompensation when the lead amount A determined according to eachparameter is less than the prescribed value A1, and determines the leadamount Apk to be the first lead amount Apk1. Also, the lead amountdetermining unit 134 makes a judgment to perform secondary phase leadcompensation when the lead amount A is the prescribed value A1 orgreater, and determines the lead amount Apk to be the second lead amountApk2. The lead amount A can be set in advance using map data, etc.

The first switching unit 138 performs switching so as to perform phaselead compensation only by the first phase lead compensator 136 when thefirst lead amount Apk1 is selected. Also, the first switching unit 138performs switching so as to perform phase lead compensation with thefirst phase lead compensator 136 and the second phase lead compensator137 when the second lead amount Apk2 is selected. By configuring in thisway, the first phase lead compensator 136 and the second phase leadcompensator 137 are configured to perform phase lead compensation onlywith the first phase lead compensator 136 when the lead amount A issmaller than the prescribed value A1.

The first switching unit 138 may also be configured to perform phaselead compensation only with the second phase lead compensator 137 whenperforming primary phase lead compensation. The lead amount determiningunit 134 may also input lead amount A to the first switching unit 138instead of the lead amount Apk. The first switching unit 138 can alsoperform switching based on the lead amount A input in this way. By doingthis, even if averaging is implemented on the first lead amount Apk1 andthe second lead amount Apk2, primary and secondary phase leadcompensation can be performed as appropriate.

The first switching unit 138, together with the phase compensationon/off determination unit 133, has the feedback primary indicatedpressure Ppri_FB for which lead compensation was performed by at leastone of the first phase lead compensator 136 and the second phase leadcompensator 137 according to the pulley state value M is set as thefeedback primary indicated pressure Ppri_FB. At least one of the firstphase lead compensator 136 and the second phase lead compensator 137configures the lead compensation unit that performs lead compensation ofthe feedback primary indicated pressure Ppri_FB. The feedback primaryindicated pressure Ppri_FB for which lead compensation was performed isoutput to the first phase delay compensator 145.

The first peak value frequency determination unit 141 determines a peakvalue frequency Fpk1 of the phase lead compensation. FIG. 8 is a drawingshowing the change in the PT resonance frequency Fpt according to thetransmission ratio Ratio. As shown in FIG. 8, the PT resonance frequencyFpt is smaller the larger that the transmission ratio Ratio is. For thisreason, the first peak value frequency determination unit 141 makes thepeak value frequency Fpk1 smaller the larger that the transmission ratioRatio is. By doing this, even if the PT resonance frequency Fpt changesaccording to the transmission ratio Ratio, it is possible to suppress asappropriate the frequency deviation between the PT resonance frequencyFpt and the peak value frequency Fpk1. The transmission ratio Ratio, inspecific terms, has the target transmission ratio Ratio_D input from thetarget value generating unit 131. The peak value frequency Fpk1determined by the first peak value frequency determination unit 141 isinput respectively to the first phase lead compensator 136 and thesecond phase lead compensator 137. By doing this, the first peak valuefrequency determination unit 141 is configured so as to set the peakvalue frequency Fpk of the respective phase lead compensations performedby the first phase lead compensator 136 and the second phase leadcompensator 137 based on the transmission ratio Ratio.

The delay amount determination unit 142 determines a delay amount Bpk.The delay amount determination unit 142 is provided in the wake of thephase compensation on/off determination unit 133. The delay amountdetermination unit 142 is provided in this way in light of placement inthe signal path. The delay amount determination unit 142 determines thedelay amount Bpk according to the on/off command, said another way,according to the on/off determination of the phase compensation. Thedelay amount determination unit 142 determines the delay amount Bpk tobe zero when the off command is input. The delay amount determinationunit 142 determines the delay amount Bpk according to the operatingstate of the vehicle when the on command is input. As parametersindicating the operating state of the vehicle, input to the delay amountdetermination unit 142 are the FB gain G_FB, the rotation speed Npri,the input torque Tsec, the transmission ratio Ratio, the secondarypressure Psec, the vehicle acceleration, the brake operating state, theprimary pressure Ppri, the engine torque, the torque ratio of the torqueconverter, the engagement state of the LU clutch 2 a, the oiltemperature TMP, etc. The delay amount determination unit 142 determinesthe delay amount Bpk according to this plurality of parameters. Saidanother way, the delay amount Bpk is made to vary according to theoperating state of the vehicle. The delay amount determination unit 142may also have the delay amount Bpk be varied according to any one ofthis plurality of parameters.

The delay amount determination unit 142, by determining the delay amountBpk according to each parameter, is able to make this variable accordingto the operating state, and can set the delay amount B at the targetedfrequency. When increasing the delay amount B, this is limited to arange for which stable operation is possible, considering therelationship with the specific specifications of the transmission ratiocontrol system 100 such as the variator 20, etc. This limit can be foundin advance by calculation or experimentation as the limit amountaccording to each parameter. The delay amount Bpk is determined byfurther reducing the delay amount Bpk actually determined according toeach parameter by the amount of the limit amount set according to eachparameter.

The delay amount determination unit 142 determines a first delay amountBpk1 and a second delay amount Bpk2 based on the determined delay amountBpk. The first delay amount Bpk1 is set corresponding to when performingthe primary phase delay compensation described later, and the seconddelay amount Bpk2 is set corresponding to when performing the secondaryphase delay compensation described later. The second delay amount Bpk2is set to ½ the first delay amount Bpk1. The delay amount Bpk determinedaccording to each parameter is set so as to correspond with the seconddelay amount Bpk2. The delay amount Bpk determined according to eachparameter may also be set so as to correspond to the first delay amountBpk1. The delay amount Bpk is input from the delay amount determinationunit 142 to the delay amount filter unit 143.

The delay amount filter unit 143 is provided in the wake of the delayamount determination unit 142, and performs filter processing of thedelay amount Bpk. The delay amount filter unit 143 is provided in thisway in light of placement in the signal path. The delay amount filterunit 143 is specifically a low pass filter unit, and is configured usinga first order low pass filter, for example. By performing filterprocessing of the delay amount Bpk, when on/off of the phasecompensation is switched, the delay amount filter unit 143 configures again averaging unit for performing averaging of changes in gain of thephase delay compensation according to determination of on/off of phasecompensation. By performing averaging of changes in gain, there issuppression of the change amount of the gain accompanying switching ofon/off of the phase compensation.

The second peak value frequency determination unit 144 determines thepeak value frequency Fpk2 of the phase delay compensation. The secondpeak value frequency determination unit 144 changes the peak valuefrequency Fpk2 by determining the peak value frequency Fpk2 according tothe peak value frequency Fpk1. FIG. 6 is a drawing representing phasedelay frequency characteristics. When the first phase lead compensator136 and/or the second phase lead compensator 137 (hereafter also notedas simply “phase lead compensator”) are turned on, it is possible toreduce vehicle vibration due to PT resonance in the PT resonanceoccurrence region. However, because high frequency gain rises, controlbecomes destabilized. In light of that, when the first phase delaycompensator 145 and/or the second phase delay compensator 146 (hereafteralso noted simply as “phase delay compensator”) are turned on, bylowering the high frequency gain of the delay peak value frequency Fpk2or greater, it is possible to suppress destabilization of control.

However, low frequency responses slower than the PT resonance frequencybecome vibrational, and the amount advanced by the phase leadcompensator is reduced. Also, there is a frequency at which the delayamount becomes the peak in the phase delay compensator, and the fartheraway from that peak value, the more the delay amount is reduced. Inaddition, the PT resonance frequency changes according to thetransmission ratio Ratio. For that reason, when the delay peak valuefrequency Fpk2 of the phase delay compensator is fixed, the PT resonancefrequency Fpt changes according to the transmission ratio changes, andends up approaching the delay peak value frequency Fpk2. If, forexample, the delay peak value frequency Fpk2 and the PT resonancefrequency Fpt approach each other, the closer they are, the more thedelay amount increases, reducing the vehicle vibration reduction effect.To avoid this, when the delay peak value frequency Fpk2 is set to beslower than necessary, by the effect of lowering the gain of peak valuefrequency Fpk2 or greater, the gain of the frequency necessary forcontrol decreases. In light of that, because vehicle vibration isreduced without lowering the gain of the necessary frequency, the peakvalue frequency Fpk2 of the phase delay compensator was applied to thePT resonance frequency, the phase lead amount, and the phase delayamount.

FIG. 7 is a drawing representing the relationship between the peak valuefrequency of the lead compensation and the peak value frequency of thedelay compensation. The horizontal axis is frequency, and the verticalaxis is phase. The lead compensation is shown by the dot-dash line, andthe delay compensation is shown by the solid line. It is preferable thatthe relationship between the peak value frequency Fpk1 in the leadcompensator and the peak value frequency Fpk2 of the phase delaycompensator be the relationship shown in FIG. 7. This is because in thiscase, it is possible to avoid the lead amount of the peak valuefrequency Fpk1 and the delay amount of the peak value frequency Fpk2from overlapping on the frequency axis, so the two do not cancel eachother. f2 in FIG. 7 is a frequency that should be separated from thelead amount and the delay amount. f2 is a fixed value, and is 1/10 ofthe PT resonance frequency Fpt. f1 is a frequency for which the peakvalue frequency Fpk2 should be separated from the 12 low frequency sideend part. f3 is a frequency for which the peak value frequency Fpk1should be separated from the f2 high frequency side end part. When thelead amount is A, and the delay amount is B, f1, f2, f3 are expressed bythe following relational expression.f1=Fpk2{(1+sin B)/(1−sin B)}^(1/2)f2=Fpt/10f3=Fpk1{(1+sin A)/(1−sin A)}^(1/2)

Here, in actuality, the peak value frequency Fpk1 of the high frequencyside is set between 2 to 5 Hz, for example, and the lead amount A isdetermined. With this value as a reference, the peak value frequencyFpk2 and the delay amount B of the low frequency side corresponding tothe position separated by the amount of the value for which f1, f2, andf3 are added are determined. By doing this, it is possible to set anappropriate position for the peak value frequencies Fpk2 and Fpk1, andpossible to ensure an appropriate control gain while ensuring thevehicle vibration reduction effect.

The peak value frequency Fpk2 determined by the second peak valuefrequency determination unit 144 is input respectively to the firstphase delay compensator 145 and the second phase delay compensator 146.By doing this, the second peak value frequency determination unit 144 isconfigured to set the peak value frequency Fpk2 of the respective phasedelay compensations performed by the first phase delay compensator 145and the second phase delay compensator 146 based on the transmissionratio Ratio.

The delay amount Bpk from the delay amount filter unit 143 is input tothe first phase delay compensator 145, the second phase delaycompensator 146, and the second switching unit 147. The peak valuefrequency Fpk2 from the second peak value frequency determination unit144 is also input to the first phase delay compensator 145 and thesecond phase delay compensator 146. The primary phase delay compensationof the feedback primary indicated pressure Ppri_FB is performed based onthe delay amount Bpk input for both the first phase delay compensator145 and the second phase delay compensator 146, and further on the inputpeak value frequency Fpk2. By performing phase delay compensation of thefeedback primary indicated pressure Ppri_FB, phase delay compensation ofthe feedback transmission control of the transmission 4 is performed.The first phase delay compensator 145 and the second phase delaycompensator 146 are specifically configured by a primary filter, and byperforming filter processing according to the input delay amount Bpk,and further to the input peak value frequency Fpk2, the primary phasedelay compensation of the feedback primary indicated pressure Ppri_FB isperformed.

The second phase delay compensator 146 is provided in series with thefirst phase delay compensator 145. The second phase delay compensator146 is provided in this way in light of placement in the signal path.The second phase delay compensator 146 has input the feedback primaryindicated pressure Ppri_FB for which primary phase delay compensationwas performed by the first phase delay compensator 145. Therefore, whenthe second phase delay compensator 146 performs the primary phase delaycompensation of the feedback primary indicated pressure Ppri_FB, itfurther performs the primary phase delay compensation again. By doingthis, the secondary phase delay compensation of the feedback primaryindicated pressure Ppri_FB is performed. The second phase delaycompensator 146 configures the delay compensation unit together with thefirst phase delay compensator 146.

The second switching unit 147 switches between when performing phasedelay compensation by the first phase delay compensator 145 and thesecond phase delay compensator 146 according to the input delay amountBpk, in other words, when performing secondary phase delay compensation,and when performing phase delay compensation only by the first phasedelay compensator 145, in other words, when performing the primary phasedelay compensation. By performing secondary phase delay compensation,compared to when performing primary phase delay compensation, it ispossible to narrow the range affected by the delay amount. Thus, it ispossible to avoid immediately reaching the stable limit without needingto lower the peak frequency Fpk2. Also, when the delay amount B of theprimary phase delay compensation according to the feedback primaryindicated pressure Ppri_FB is smaller than a prescribed value B1, phasedelay compensation is performed only with the first phase delaycompensator 145, and when the delay amount B is greater than theprescribed value B1, secondary phase delay compensation is performedusing the second phase delay compensator.

In this way, for performing phase delay compensation, the delay amountdetermination unit 142 and the second switching unit 147 arespecifically configured as follows. Specifically, the delay amountdetermination unit 142 makes a judgment to perform primary phase delaycompensation when the delay amount B determined according to eachparameter is smaller than the prescribed value B1, and determines thatthe delay amount Bpk is the first delay amount Bpk1. Also, the delayamount determination unit 142 makes a judgment to perform the secondaryphase delay compensation when the delay amount B is the prescribed valueB1 or greater, and determines that the delay amount Bpk is the seconddelay amount Bpk2. The delay amount B can be set in advance using mapdata, etc.

The second switching unit 147 performs switching so that when the firstdelay amount Bpk1 is selected, phase delay compensation is performedonly by the first phase delay compensator 145. Also, when the seconddelay amount Bpk2 is selected, the second switching unit 147 performsswitching so that phase delay compensation is performed by the firstphase delay compensator 145 and the second phase delay compensator 146.By configuring in this way, the first phase delay compensator 145 andthe second phase delay compensator 146 are configured to perform phasedelay compensation only by the first phase delay compensator 145 whenthe delay amount B is smaller than the prescribed value B1.Specifically, the more the delay amount of the phase delay compensatorincreases, the more it is possible to reduce the phase delay of the peakfrequency range. For that reason, since the low frequency phase delayfor which control excitation occurs is eliminated, control excitationdoes not occur easily. However, from when the delay amount exceeds 40deg., for example, the drop amount of high frequency gain is reduced,decreasing robustness. Thus, when the delay amount is lower than 40deg., the demerits of changing to secondary mode are stronger, so onlythe first phase delay compensator 145 is used.

The second switching unit 147 may also be configured to perform phasedelay compensation only by the second phase delay compensator 146 whenperforming primary phase delay compensation. The delay amountdetermination unit 142 may also have the delay amount B input to thesecond switching unit 147 instead of the delay amount Bpk. The secondswitching unit 147 may also perform switching based on the delay amountB input in this way. By doing this, even if averaging is implemented onthe first delay amount Bpk1 or the second delay amount Bpk2, the primaryand secondary phase delay compensation can be performed as appropriate.

The second switching unit 147, together with the phase compensationon/off determination unit 133, configures a setting unit that sets asthe feedback primary indicated pressure Ppri_FB the feedback primaryindicated pressure Ppri_FB for which delay compensation was performed byat least one of the first phase delay compensator 136 and the secondphase delay compensator 137 according to the pulley state value M. Atleast one of the first phase delay compensator 136 and the second phasedelay compensator 137 configures the delay compensation unit thatperforms the delay compensation of the feedback primary indicatedpressure Ppri_FB. The feedback primary indicated pressure Ppri_FB forwhich delay compensation was performed configures the feedback commandvalue after compensation.

Input to the actuator 111 are the feedback primary indicated pressurePpri_FB selected from the first switching unit 138, and a primaryindicated pressure Ppri_FF (not illustrated) set based on the targettransmission ratio Ratio_D (the target primary indicated pressure thatdetermines balance thrust or transmission ratio). The actuator 111 is aprimary pressure control valve that controls the primary pressure Ppriprovided in the hydraulic control circuit 11, for example, and controlsthe primary pressure Ppri so that the actual pressure Ppri_A of theprimary pressure Ppri becomes the indicated pressure Ppri_D according tothe target transmission ratio Ratio_D. By doing this, the transmissionratio Ratio is controlled so that the actual transmission ratio Ratio_Abecomes the target transmission ratio Ratio_D.

A sensor unit 40 detects the actual transmission ratio Ratio_A of thevariator 20. The sensor unit 40 is specifically configured by therotation speed sensor 42 and the rotation speed sensor 43. The actualtransmission ratio Ratio_A that is the actual value (sensor value) ofthe transmission ratio detected by the sensor unit 40 is input to thesensor value filter unit 140. An on/off command is also input via theon/off command filter unit 139 to the sensor value filter unit 140.

The on/off command filter unit 139 outputs an on command to the sensorvalue filter unit 140 when the lead compensation is on, outputs an offcommand to the sensor value filter unit 140 when the lead compensationis off. The on/off command filter unit 139 may also be omitted.

The sensor value filter unit 140 performs filter processing of theactual transmission ratio Ratio_A. With the sensor value filter unit140, the mode of the filter processing is changed according to theon/off command. In specific terms, with the sensor value filter unit140, the filter processing order or execution/stopping is switchedaccording to the on/off command. The sensor value filter unit 140 is afirst order low pass filter when the off command is input, and is ahigher order low pass filter or filter processing is stopped when the oncommand is input.

By configuring the sensor value filter unit 140 in this way, when afirst order low pass filter is used, a slight delay occurs in the regionof a frequency to be removed or lower, whereas when the on command isinput, delay is improved. As a result, it is possible to further advancethe phase of the feedback primary indicated pressure Ppri_FB. The sensorvalue filter unit 140 can be a configuration having one or a pluralityof first order low pass filters provided with the ability to switchexecution/stop or order of filter processing, for example. The actualtransmission ratio Ratio_A from the sensor value filter unit 140 isinput to the FB compensator 132.

With the PT resonance detection unit 150, the vibration component oflongitudinal acceleration G detected by the G sensor 53 is extracted,and when the state of the amplitude of the vibration component being aprescribed value continues for a prescribed time or longer, it is judgedthat vibration is occurring. On the other hand, when the state of theamplitude of the vibration component being less than the prescribedvalue continues for a prescribed time or longer, it is judged thatvibration is not occurring.

With the oil vibration detection unit 151, first, the voltage signaldetected by the hydraulic sensor 52 is converted to a hydraulic signal,the DC component (fluctuating component according to the controlcommand) is removed by the bandpass filter processing, and only thevibration component is extracted. Then, the amplitude of the vibrationcomponent is calculated, and when the state of the amplitude of thehydraulic signal being the prescribed amplitude or greater continues fora prescribed time or longer, it is judged that oil vibration isoccurring. On the other hand, when oil vibration is occurring, when thestate of the amplitude being less than the prescribed amplitudecontinues for the prescribed time or longer, it is judged that oilvibration is not occurring. As the hydraulic signal, it is possible touse the primary pulley hydraulic pressure, or to use both.

With the divergence detection unit 152, a detection is made of whetherthe final command signal is diverging. Here, divergence of the commandsignal is detected based on whether the frequency is a prescribed valueor greater, and whether the state of the amplitude being a prescribedvalue or greater has continued for a prescribed time.

As explained above, with the embodiment, the following operationaleffects are obtained.

(1) The control device of a continuously variable transmission thatperforms feedback control of the transmission 4 so that the actualpressure Ppri_A becomes the indicated pressure Ppri_D, comprising

a phase lead compensation unit that performs phase lead compensation ofthe feedback control,

a phase delay compensation unit that performs phase delay compensationof the feedback control,

a first peak value frequency determination unit 141 that changes thepeak value frequency Fpk1 of the phase lead compensation according tothe transmission ratio Ratio of the transmission 4, and

a second peak value frequency determination unit 144 that changes thepeak value frequency Fpk2 of the phase delay compensation based on thepeak value frequency Fpk1 of the lead compensation.

Thus, even if the transmission ratio Ratio changes, and the PT resonancefrequency Fpt changes, by changing the peak value frequency Fpk1 of thephase lead compensation according to the transmission ratio Ratio, it ispossible to suppress frequency deviation between the PT resonancefrequency Fpt and the peak value frequency Fpk1. For this reason, it ispossible to avoid a reduction in the suppression effect by phase leadcompensation according to changes in the PT resonance frequency Fpt.Also, by setting the delay amount B, it is possible to ensure thestability of the transmission control system 100 in a case when the leadamount is made larger. Also, by changing the peak value frequency Fpk2based on the peak value frequency Fpk1, it is possible to avoid lowfrequency control excitation while avoiding vehicle vibration caused byPT resonance.

(2) The first peak value frequency determining unit 141 makes the peakvalue frequency of the phase lead compensation smaller the larger thetransmission ratio Ratio is, and

the second peak value frequency determination unit 144 makes the peakvalue frequency Fpk2 of the phase delay compensation smaller the smallerthe peak value frequency Fpk1 of the phase lead compensation is. Thismakes it possible to avoid canceling of each other by the lead amount Aand the delay amount B by overlapping, and possible to realizeappropriate feedback control.

(3) The second peak value frequency determination unit 144 makes thepeak value frequency Fpk2 of the phase delay compensation smaller thelarger the delay amount B of the phase delay compensation unit is.Specifically, because the range expansion of the phase is greater thelarger the delay amount B is, by making the peak value frequency Fpk2smaller, it is possible to avoid canceling of each other by the leadamount A and the delay amount B by overlapping, and possible to realizeappropriate feedback control.

(4) The second peak value frequency determination unit 144 makes thepeak value frequency Fpk2 of the phase delay compensation smaller thelarger the lead amount A of the phase lead compensation unit is.Specifically, because the expansion of the range of the phase is largerthe larger the lead amount A is, by making the peak value frequency Fpk2smaller, it is possible to avoid canceling of each other by the leadamount A and the delay amount B by overlapping, and possible to realizeappropriate feedback control.

Other Embodiments

Above, a mode for carrying out the present invention was explained basedon the embodiment, but the specific configuration of the presentinvention is not limited to the configuration shown in the embodiment,and even if there are design changes, etc., in a range that does notdepart from the gist of the invention, these are included in the presentinvention.

With the embodiment, an example was shown with the first phase leadcompensator 136 and the second phase lead compensator 137 configuredseparately, and similarly the first phase delay compensator 145 and thesecond phase delay compensator 146 being configured separately, but itis also possible to configure with only one of the compensators. Also,with the embodiment, the first peak value frequency determination unit141 determined the peak value frequency Fpk1 according to the targettransmission ratio Ratio_D, but it is also possible to determine thepeak value frequency Fpk1 based on the actual transmission ratioRatio_A. By doing this, even in a case when there is divergence betweenthe target transmission ratio Ratio_D and the actual transmission ratioRatio_A, it is possible for the peak value frequency Fpk1 to approachthe targeted frequency.

Also, with the embodiment, a configuration was shown in which servosystem feedback control is performed based on the transmission ratio,but it is also possible to have a configuration in which feedbackcontrol is performed according to fluctuation of the input torque. Also,with the embodiment, an example of the abovementioned control beingconfigured within the transmission controller 12 was shown, but it isalso possible to realize this with a plurality of controllers.

The invention claimed is:
 1. A control device for a continuouslyvariable transmission that performs feedback control so that an actualtransmission control value becomes a target transmission control value,the control device for a continuously variable transmission comprising:a phase lead compensation unit configured to perform phase leadcompensation of the feedback control; a phase delay compensation unitconfigured to perform phase delay compensation of the feedback control;a first peak value frequency determination unit configured to change apeak value frequency of the phase lead compensation according to atransmission ratio of the continuously variable transmission; and asecond peak value frequency determination unit configured to change apeak value frequency of the phase delay compensation based on the peakvalue frequency of the lead compensation.
 2. The control device for acontinuously variable transmission of claim 1, wherein the first peakvalue frequency determination unit is configured to set the peak valuefrequency of the phase lead compensation so that the larger thetransmission ratio is, the smaller the peak value frequency of the phaselead compensation is; and the second peak value frequency determinationunit is configured to set the peak value frequency of the phase delaycompensation so that the smaller the peak value frequency of the phaselead compensation is, the smaller the peak value frequency of the phasedelay compensation is.
 3. The control device for a continuously variabletransmission of claim 1, wherein the second peak value frequencydetermination unit is configured to set the peak value frequency of thephase delay compensation so that the larger the delay amount of thephase delay compensation unit is, the smaller the peak value frequencyof the phase delay compensation is.
 4. The control device for acontinuously variable transmission of claim 1, wherein the second peakvalue frequency determination unit is configured to set the peak valuefrequency of the phase delay compensation so that the larger the leadamount of the phase lead compensation unit is, the smaller the peakvalue frequency of the phase delay compensation is.
 5. A control methodfor a continuously variable transmission that performs feedback controlso that an actual transmission control value becomes a targettransmission control value, the control method comprising: performingphase lead compensation of the feedback control and phase delaycompensation of the feedback control; changing a peak value frequency ofthe phase lead compensation according to a transmission ratio of thecontinuously variable transmission; and changing a peak value frequencyof the phase delay compensation based on the peak value frequency of thelead compensation.